use pull for array elements in mongoose code example

Example 1: $pull mongoose

TemplateDoc.findOneAndUpdate(
    { userId: _id },
    { $pull: { templates: { _id: templateid } } },
    { new: true }
  )
    .then(templates => console.log(templates))
    .catch(err => console.log(err));

Example 2: mongoose remove element from array

db.survey.update( // select your doc in moongo
    { }, // your query, usually match by _id
    { $pull: { results: { $elemMatch: { score: 8 , item: "B" } } } }, // item(s) to match from array you want to pull/remove
    { multi: true } // set this to true if you want to remove multiple elements.
)